One type of vibration damper is known from DE 44 41 047 C1. Pressure-dependent damping valves are provided on a piston guided axially within a cylinder tube in order to allow fluid to be exchanged between two working spaces in the extension and compression stage. Pilot control is exercised in such a way that a controllable pressure is built up in pilot chambers. The pilot pressure pushes the valve disks of the damping valves toward the closed position thereof. By means of a bypass channel system, fluid is passed out of the working spaces into the pilot chambers, thus increasing the pressure there. The pilot pressure is controlled with the aid of an externally adjustable pilot valve arranged in the bypass channel system. An elastic element forms the division between the pilot chamber and the working space.
Another vibration damper, which operates on the same principle, is known from DE 101 04 640 C1. In this document, the pilot chambers are formed by pressure spaces. These pressure spaces are each formed by a pressure space housing and a seal, which rests movably on a damping valve.
WO 2010/122102 A1 discloses another vibration damper, which operates on the same principle. An upstream restrictor, through which hydraulic oil can flow into the bypass channel system, is embodied by a bore of fixed cross section in a housing part of the damping valve.
An upstream restrictor for a similar application is provided in U.S. Pat. No. 7,694,785 B2. This upstream restrictor is formed by a disk pack, by means of which the main damping valve is also formed.
However, the construction of the valve subassemblies of these vibration dampers is quite complex in some cases or requires specific components that, in some cases, are quite expensive to produce. Moreover, it is often not possible to change the characteristic only of individual functions of the damper in a selective manner for other areas of application simply by replacing individual components.